Induction Motor State Observer with Online Tuning of Main Parameters

Induction motors are widely used in heavy traction applications. The proper operation of their control system is strongly dependent on knowledge of the motor parameters. These parameters can vary during operation due to temperature deviation and operating conditions. This paper proposes induction motor state observer with automatic online tuning of mutual inductance and rotor resistance which are most important for operation of field-oriented control. The mutual inductance mostly varies as a function of the magnetizing current and the rotor resistance varies with the change of the rotor temperature. The proposed observer estimates rotor flux linkage and then recalculates the stator voltage. Comparing recalculated and applied voltages the correction of the motor parameters is made. Simulation results are provided to prove the efficiency of the proposed method.